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Interactive Simulations for Teaching Physics
Fermat's Principle: Reflection
Authors: Ms. Giselle dos Santos Castro - Federal University of Ceara - UFC
Dr. Nildo Loiola Dias - Federal University of Ceara - UFC
CONTROLS:
- Drag point A to any position.
- Drag point B to any position.
- Drag point P on the plane mirror in order to obtain a minimum travel time APB. The (<<) and (>>) buttons allow fine control of the point position, P.
- Click the SHOW NORMAL button to trace the surface normal at point P.
- Click the PROTRACTOR button to get a protractor that can be moved to the desired position.
- Click on the SHOW PROLONGATION button to extend the incident and reflected rays in order to facilitate (when necessary) the measurement of angles.
DESCRIPTION OF THE SIMULATION:
This simulation makes it possible to verify that, according to Fermat's Principle, in light reflection, the path taken by light between two points located in a medium, but passing through a point on a mirror, will be the one for which the travel time is minimal. For this, it is possible to position points A and B in any position and locate a point P, on the surface of the mirror, in order to minimize the travel time of the light. Localizing the point P that minimizes the travel time, it is possible to measure the incidence and reflection angles with a protractor and verify that they are in accordance with the laws of reflection.
For an analysis of the data, consult one of the proposed ACTIVITY GUIDE.
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